feat: Add new helper to get BlessedReplicaVersions (#6463)

The structure follows the existing helpers in the directory

Author: frankdavid

rs/registry/helpers/src/blessed_replica_version.rs

@@ -0,0 +1,21 @@
+use crate::deserialize_registry_value;
+use ic_base_types::RegistryVersion;
+use ic_interfaces_registry::{RegistryClient, RegistryClientResult};
+use ic_protobuf::registry::replica_version::v1::BlessedReplicaVersions;
+use ic_registry_keys::make_blessed_replica_versions_key;
+
+pub trait BlessedReplicaVersionRegistry {
+    fn get_blessed_replica_versions(
+        &self,
+        version: RegistryVersion,
+    ) -> RegistryClientResult<BlessedReplicaVersions>;
+}
+
+impl<T: RegistryClient + ?Sized> BlessedReplicaVersionRegistry for T {
+    fn get_blessed_replica_versions(
+        &self,
+        version: RegistryVersion,
+    ) -> RegistryClientResult<BlessedReplicaVersions> {
+        deserialize_registry_value(self.get_value(&make_blessed_replica_versions_key(), version))
+    }
+}

rs/registry/helpers/src/lib.rs

@@ -4,6 +4,7 @@
 //! to the respective crate/component at some point in the future.
 
 pub mod api_boundary_node;
+pub mod blessed_replica_version;
 pub mod chain_keys;
 pub mod crypto;
 pub mod ecdsa_keys;